A semiconductor module usually includes: a substrate having a conductive pattern; a semiconductor device having a back side bonded to the conductive pattern, and a front side provided with a front-side electrode; and a bonding wire bonded to the front-side electrode. The substrate, the semiconductor device, and the bonding wire are usually sealed with a sealing material, such as a thermosetting resin or a gelled resin.
One example of such a semiconductor module is described in PTD 1 (Japanese Patent Laying-Open No. 2009-302261). In the semiconductor module described in PTD 1, for the purpose of diffusion of heat generated from a semiconductor chip, a bonding portion between a bonding wire and a front-side electrode of a semiconductor device is coated with a coating layer having a high heat conductivity. The coating layer is copper (Cu) or the like formed by, for example, vapor deposition.